The largest animal to have ever lived on Earth is the blue whale (Balaenoptera musculus). These magnificent mammals can reach lengths of up to 100 feet (30 meters) and weigh as much as 200 tons or more. Blue whales are found in oceans around the globe and are known for their distinctive blue-gray coloration with lighter spots. They primarily feed on small shrimp-like animals called krill, consuming up to 4 tons of them each day during feeding seasons. Despite their enormous size, blue whales are gentle giants and are currently listed as endangered due to past whaling activities and ongoing threats to their habitat.